One of the things we had planned for v3.0, was a sound-replacement system. We hadn't expected it to be quite this powerful, though. This technology allows monsters, trains, items, pushables... anything (except for a few client-side sounds, though we're working on that) to use any set of sounds a mapper specifies.
Map makers can specify as many or as few sounds to be replaced as they wish... you could just replace a monster's attack sound, or you could replace all of its sounds... pain sounds, speech samples, etc.
And the replacement system works per-entity (though there's also a global system you can use in conjunction with the per-entity system). You could have ten different headcrabs in a map, and each of them could have its own unique set of sounds.
Together with our existing mapping technologies (per-entity model replacement, per-monster health, per-map skill config, etc.), this allows mappers to add unique enemies to their maps without any programming. A forum has been created on the SvenCo-op site for the release of Monster Packs, compilations of all the models, sounds, and config files needed to plug a custom monster into your map.
Several packs are available already, including an Archer Fish and a flamethrower-wielding robogrunt. Head over to the Monster Pack Showcase forum now, and check them out! Also included on the forum is information on how to create your own monster pack.
Lastly: Remember to keep an eye on the site over the next week, or thereabouts... the next announcement could be considered a lot bigger than this one, depending on your point of view.
